Laser beams are generated by means of a population inversion consisting of an unstable abundance of molecules having excited high energy electronic states which release photons as they decay to the equilibrium lower energy states of the optically active media.
In high energy chemical lasers, the excited electronic states are generated by a chemical reaction. For example, one such reaction involves the use of excited molecular oxygen, hereinafter referred to as singlet delta oxygen (SDO) or O2(1Δ), in combination with an optically active media or lasing substance, such as iodine or fluorine.
One method presently in use for generating a stream of SDO involves a chemical reaction between chlorine gas and a basic solution of hydrogen peroxide, hereinafter referred to as basic hydrogen peroxide (BHP). The excited oxygen can then be added to a suitable lasing medium and the mixture passed through an optical resonator/cavity to bring about a lasing action.
These lasers have been found to be very useful but improved performance characteristics, especially in the area of materials supply and efficiency, is desirable. In particular, a number of problems in the supply, storage, and maintenance of the BHP reactant material has limited the use of these chemical lasers in military and airborne applications.
For example, a high-performance tactical laser weapon requires a laser with rapid fire capability. Many lasers, such as chemical oxygen iodine lasers (COILs) (e.g., the Advanced Tactical Laser (ATL) Advanced Component Technology Demonstration (ACTD)), can operate only in a short lasing burst limited by the supply of BHP. In the ATL, the airborne laser (ABL), and the EC-COIL laser systems, each laser burst is separated by a longer time period during which spent and excess BHP is recycled and/or regenerated to support another lasing burst. This limits the utility of laser weapons and hence their potential.
In order to improve the efficiency of BHP supply via recirculation and/or regeneration, it is essential to provide the laser fuel “status” in real time to permit the user to know the condition of the fuel prior to lasing and during recycling or regeneration. Currently, a system or method for real time in situ monitoring of BHP solution (for concentration or component analysis or diagnostics) is not available. Instead, BHP characterization currently requires batch sampling of BHP before and after reaction followed by titrations to determine the solution content, thereby requiring hours of labor and cost and resulting in great inefficiencies in the BHP supply.
Thus, a real time and in situ system and method for monitoring or analyzing a solution including hydrogen peroxide (e.g., BHP) is highly desirable and advantageous.